3,3'-Oxy-bis([2,2'-di(bromomethyl)]propanoic acid), referred to hereinafter as "diacid" for the sake of brevity, has the formula: ##STR2##
The diacid is, in turn, a derivative of the well-know flame-retardant compound Didinol, which is employed to obtain V-2 polypropylene (according to UL94 standard), and which has the formula: ##STR3##
The art is constantly seeking for flame-retardant agents which present high thermal stability as well as high melting points. The thermal properties of the flame-retardant compounds are of paramount importance in the preparation of flame-retardant compositions and articles which incorporate them, because of the relatively high temperatures that these compounds are required to withstand during processing of plastics. On the other hand, health and evironmental requirements make it preferable to provide compounds which are free from the danger of liberating dioxines or benzofurans.